This invention relates to stair mounted elevators or lifts, commonly known as stairlifts.
Stairlifts, in the form of a carriage mounted for movement along a rail, are well known for moving aged or handicapped persons up and down staircases.
In our pending International Patent Application PCT/GB99/03447 we describe and claim a form of stairlift in which the stairlift carriage is supported on a narrow tubular rail including four rolling surfaces arranged about the rail cross-section at 45xc2x0 to a horizontal plane through the rail. To this end, the carriage includes roller pairs which bear on the rolling surfaces extending along the rail, and the above application describes how these rollers are provided in upper and lower pairs. The pending application further describes the use of axle pins mounted in eccentric through bores in the lower rollers which allows adjustment of the lower rollers to take up unwanted play between the carriage and the rail.
In practice, we have found that the particular rail and carriage configuration does not best lend itself to adjustment in the manner described. Further, accessing and manipulating the eccentric mounts of the lower rollers can be difficult for an installer.
It is an object of this invention to provide a stairlift which allows adjustment in installation and/or operation which addresses the aforementioned problems, or which will at least provides a useful choice.
Accordingly, in one aspect, the invention provides a stairlift carriage for movement along a stairlift rail, said carriage including:
a plurality of first rollers arranged to engage said rail from a first direction;
a plurality of second rollers arranged to engage said rail from a second direction, said second direction being substantially opposed to said first direction; and
adjustment means operable to adjust the spacing between at some of said first rollers and said second rollers, said carriage being characterised in that said adjustment means includes a common member on which at least two of said first rollers are mounted and displacement means operable to displace said common member towards said second rollers.
Preferably all of said first rollers are mounted on said common member.
Preferably said carriage further includes a spaced pair of side plates which, when said carriage is in its normal operating position, overlie opposite sides of said rail, wherein said rollers are mounted to project inwardly from said side plates.
Preferably said displacement means is operable to displace said common member with respect to the side plate from which said first rollers project. Said displacement means conveniently comprises one or more grub screws, each grub screw being mounted in a stud fixed to said side plate.
In a second aspect the invention provides a stairlift including the carriage as herein before set forth.
Many variations in the way the present invention may be performed will present themselves to those skilled in the art. The description which follows is intended as an illustration only and the absence of description of particular alternatives or variants should in no way be applied to limit the scope of the invention. Such description of specific elements which follows should also be interpreted as including equivalents whether existing now or in the future. The scope of the invention should be defined solely by the appended claims.